Portable scaffolding



March 4, 1947. w PQHRMAN 2,416,950

PORTABLE 'SCAFFOLDING Filed Jan. 28, 1946 2 SheetsSheet 1 Invenior WaZi'er'AZ P012 an 25 a 2/ March 4, 1947. w. A. PO'HRMAN 2,416,950

' PORTABLE SCAFFOLDING Fil ed Jan. 28, 1946 2 Sheets-Sheet 2 Wa liezuq. Pohrman hf l flfiorz eyfzurezzior' Patented 1947 t:

UNITED STATES PTATENT o en PORTABLE SCAFFOLDING Walter A. Pohrman, Vancouver, Wash. Application January 28, 1946, Serial No. 643,879 Claims. (01. 304-3);

The object of my invention is to provide a scaffold of the ladder-type which has its greatest use in shipbuilding,-within houses and other areas which require a scaffold to be passed through narrow openings and to be quickly and easily assembled and disassembled. The object of my invention is to provide a scaffold of this type of two ladder sections and one or more boards or scaffold planks which extend between the ladder sections and constitute a platform. The arrangement of the rungs of the ladder sections, their spacing and disposition cause the parts to so engage each other that they serve to prop and give rigidity to the scaffold without requiring auxiliary fastening devices or other supports.

A further and more specific object of my invention is to provide a ladder structure of this character which may be used in connection with the construction of a portable scaffold, which ladder structure is strong and rigid and securely grips and holds platforms to promote stability in a portable scaffold.

The details of my invention and the mode of operation thereof are hereinafter described with reference to the accompanying drawings in which:

Fig. 1 is a perspective view of a scaffold constructed in accordance with my invention;

Fig. 2 is an enlarged sectional view of the bottom portion of a ladder, said section being taken on the line 2-2 in Fig. 1; r

Fig. 3 is a fragmentary sectional detail taken on a line 3-3 in Fig. 2;

Fig. 4 is a perspective view of a modification of my invention in which aplurality of planks or boards may be supported by the two ladder sections; and

Fig. 5 is a sectional detail of a modified type of foot for a ladder element, portions of said structure being shown broken away to disclos details of construction. I

- A portable scaffold embodying my invention comprises two ladder sections and a joining platform or scafiolding board. The ladder sections are identical and are thus interchangeable. In

the drawings the left hand ladder section is given reference character A and the righthand section is B. Because of the fact that said sections are identical the same reference characters are given to the parts thereof.

Said ladder sections comprise two uprights l and 2 and said uprights preferably are structural channel sections or are U-shapedin cross-section. Th s. is not essentialbut it .is'desirable because 2 the legs of said U-shaped sections may straddl the rungs and be welded thereto, as will hereinafter be described. Said uprights preferably con'- verge toward their upper ends 3 and 4 and are spaced more widely at their lower ends 5 and 6. This tends to promote lateral stability and is common in ladders.

A plurality of rungs are joined between said uprights. In Fig. 2 the lower rung I is illustrated and it is to be noted that said'rung is welded between the spaced U-shaped portions 2a of the upright 2 s0 asto be securely joined. It is to be understood that both ends of each rung are welded in place within the straddling portions of the uprights. Said rungs 'l, 9, l0, l2, l3, l4, and [5 are of the same diameter which closely approximates the spacing of the lateral flanges of the two uprights l and 2. As is shown in Fig. 2 this fit is quite nug and thus if welds are made at both sides of the pipe and inside of each of said flanges 2a the welds form virtually cradles in which said rungs lie. That is, fillet welds may be made at both sides of each rung and at each end thereof which secure saidrungs within-the U-shaped structure of the uprights at the ends and along both sides of the rung adjacent said ends. Said fillet welds form virtually wedges inclined substantially tangential to the periphery of the rung and thus a secure structure is formed.

At convenient heights in said ladders, pairs of rungs are arranged as pairs 9 and T0, I2 and I3,

and I4 and I 5. Said pairsare spaced apart a distance only slightly greater than the thickness of the scaffold plank or platform ll. That is, said pairs of rungs will easily accomodate said cross plank or platform when the ladder sections are parallel but when the ladder sections are moved so that their lower ends 5 and 6 are spaced apart more widely, the said board or platform-l l is pinched between and gripped'by the pairs of rungs between which it lies. The location of said spaced pairs above the lower ends 5 and 6 sired to move said scaffolding plank to a higher location it would be arranged between the run'gs I4 and I5 and if it were desired to lower the scaffolding plank it might'be supported by the rung l0 and be gripped upon its upper surface by. the other rung 9 of said pair. v i

To prevent the lower ends and 6 of theladder sections from slipping it is desirable that they be provided with feet It made of hardwood or other non-metallic substance providing good frictional engagement with a floor, and without marking or scarring said floor. Said feet are joined to the uprights I and 2 by bolts I1. The lower or extreme end is preferably rounded at l8 so that it may .seat securely independent of the angular relation :of the ladder sections. :Said feet have a narrowed neck"! 6a which lies closely within the lateral marginal flanges 2a of the upright. It is desirable that this fit should be almost a driving fit so as to eliminate play. 7

In many instances it is desirable and necessary to comply with state or industry safety regulations to provide a platform two gplanks wide. To comply with said regulations and to provide a broader platform I make ladder sectio1:i-s"ii l3 adapted to accommodate two scaffolding planks I arranged side by side, as is shown Fig. 4..

' In :said figure I also have illustrated how said ladder sections may be .made of tubular members 21 and 22 with the'run'gs la, 19a and Illa, lid and 13a, iandzlda and 15a welded thereto. To provide two slaterally aligned but separated pockets between each of said pairs of :rungs I .arranged a longitudinally arranged stiffening :and partitioning member l9 requi-distantbetween lup- ;rights 2'! and :22, This member 119 :prevents the scaffolding planks from shifting laterally and also stiffens the .laddersection :so that it 'Will :not how, nor the rungs bend due to the greater'width of the :ladder provided to accommodate two scaffolding planks, side-by-fside. To fit the tubular form of the uprights of the ladders I make feet 10 of hardwood or similar material so :that the outside diameter of the neck porltionxZfla thereof will fit tightly within the :b ore 22a. of :the upright .22. .An encircling clamping band 123 extends about the periphery of the lower :end .of :said upright 2:2 :and ;a atransverse .bolt .24 extends adia- Jmetrically through the .collar 23, the lower end 220. of the upright 22 and the neck .2011 of :said foot to hold said parts tightly togetheriand ,rpreventglateral. movement and inadvertent disenzgagement ofsaidparts.

vMy improved portable scaffold may :be used :as follows: .In shipbuilding, for example, and :particularly between decks it isznecessary topaint or otherwise work :upon walls :and .neilings which :are out of reach of a. workman standing on the floor or deck. .Scaiioldiyng must ;be brought aboard and this either .:may be ,ail'l the form of planks or in the ,form :of horses :or other-constructed parts. If the lattenxthe roughshandling incident to swinging slings or (crowding them through narrow passageways -Dromotes extensive breakage. I-f said scaffolding .sisrpartially \preformed, as horses, and :similarzparts, then :said structure is also quite bulky. With type ;of portable scaffold the scaffolding planks 1; and the :ladder sections maybeglaid gflatwise One uppnzthe other and be c-arriedfin sling-loadsas conveniently as lumber, timbers or structural :steel :members. To set up said scafiold-ing :it gisinecessaryzonly :to select two ladder sections and pass "the ends :of one or more scaffolding planks between appropriate 'helght' rungs of :said sections, :move :said a ladder sections so :that their feet or bottom portions diverge outwardly zurrtil they fpinchsarrd ion- ;gagethe ends of ,itheyscafiolding. With this simple operation, the :scaiiolding:is:fully complete and ;is sturdy. Taking down :may be "performed in a similar expeditions Zmanner. ladder sections are merely arranged parallel and then may be spread apart and pulled off the ends of the scaifolding planks.

Although I have discussed the use of my invention in connection with shipbuilding and ship construction I do not want to consider its use limited thereto or imply that this is the field of its greatest use. Said portable scaffolding provides an extremely eflicient and sturdy support in houses and buildings tor painters plasterers and other workmen and because of the fact that said parts are all fiat and easily detached they may pass easily through doorways and other restricted apertures.

not essential that the ladder sections be made of metal and that the scaifolding planks be made of wood. There is substantial strain resisted by I the ladder sections and said strain is translated into'pin'ching stresses on the end of the scaifolding V Said pinching serves to bind vertical they impose too great bending stresses, upon the ladder sections. Insufiicient angularity of theladdersections promotes instability. Thus, .I have shown inEigs. 1 and 4 the arrangement of the parts in suggestedangu-lar position to minimize destructive strains .and to promot adequate stability. 7

.Ielaim: U

1. In a scaffold comprising a pair of ladder sections and a scaffold board supported between them, each ladder .section having uprights and .pairs of rungs joining said uprights and spaced in longitudinal alinement and at longitudinal intervals between said uprights, said rungs being adapted toreceiye and support said scaffold board between them andsaidpairsof rungsfloeing spaced apart a distance only slightly greater than. the thickness 'of' said scaffold ;,boar. d so that wvhen said ;ladders are inclined obliquely to said-scaffold board they will pinch and hold suchs afield board securely without requiring auxiliaryfasten .ing devices.

2. In a sea-field comprisingiapair of gladdersec .tions :and a scaffold board sup orted sbetween e each ladder se tion havin ul ri htsrand pairs of rungs joining said uprights ,a-nd-;s pa.ced-

in longitudinal a1inement and at ilpn tudinfi l. intervals between said uprights; said being adapted to receiveand supportsaid scaffeldboard between them, saidpair ,oftrungsbeing spaced a art adist-a-nce only slightly greaterithan th 1 thickness ofsaid scaffold board so that whenxsaid zladders are inclined obliquely'dzo 's'said' scaficld ,boardathey avill-pinchiand hold-suclrscafioldrboard securely without requiring iaiuxi'llarystasteningldevices, and said rungs being .of ici=rcular section,

this presenting icurized :sur'faces 'tokthe-zfiaces of vsaidscaiioldlavoard.

;3. In a scan-old comprising sea-11f of ladder sections sand :12. scafiold :board. supporte'd beftween them, each iladder section having upr'igh-t's and pains of "rungs :of :circular section jOinir'Ig sa'id uprights and spaced at longitudinal intervals between said :uprights, said rungs being adapted to receive and support said scafidld-boalrdlbdtiiren them, said pairs of rungs ibeingspaced apart a .distance .only slightly greater than the thickness of said sscaifold :board so that when s'a'id fladders rare zinclmedobliquely to said scaffold-board they 1 deem it desirable but f 5 will pinch and hold such scaffold board securely without requiring auxiliary fastening devices, and said uprights being of U-shaped section, the lateral walls thereof being spaced apart a distance substantially equal to the diameter of said rungs, said rungs being secured between said lateral flanges.

4. lln a scaffold comprising a pair of ladder sections and a scaffold board supported between them, each ladder section having uprights and pairs of rungs of circular section joining said uprights and spaced at longitudinal intervals between said uprights, said rungs being adapted to receive and support said scafiold board between them, said pairs of rungs being spaced apart a distance only slightly greater than the thickness of said scaffold board so that when said ladders are inclined obliquely to said scaffold board they will pinch and hold such scaffold board securely without requiring auxiliary fastening devices, and said uprights being of U-shaped section, the lateral walls thereof being spaced apart a distance substantially equal to the diameter of said rungs, said rungs being welded between said lateral flanges.

5. In a scaffold comprising a pair of ladder sections and a scaffold board supported between them, each ladder section having uprights and pairs of rungs joining said uprights and spaced at longitudinal intervals between said uprights,

said rungs being adapted to receive and support said scaflold board between them, said pairs of rungs being spaced apart a distance only slightly greater than the thickness of said scaffold board so that when said ladders are inclined obliquely to said scaffold board they will pinch and hold such scaffold board securely without requiring auxiliary fastening devices, said uprights being of U-shaped section, the lateral walls thereof being spaced apart a distance substantially equal to the diameter of said rungs, said rungs being secured between said lateral flanged and separable feet recessed in the lower ends of said U-shaped uprights, the floor engaging surfaces of such feet being curved to accommodate changes in the angular relation of the ladder sections with respect to each other and to said scaffold board.

WALTER A. POI-IRMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 60,967 Torrey Jan. 1, 1867 1,043,172 Trew Nov. 5, 1912 1,600,103 Evans Sept, 14, 1926 2,397,241 Causey Mar. 26, 1946 2,400,659 St-Mars May 21, 1946 

